Power efficient memory and cards

ABSTRACT

A memory with an internal detection mechanism to detect the presence of either an external component of an external voltage on some no connect pins, allowing a change in the configuration of the internal voltage pumps based on those detections, or which can be used as a standard device as well. The embodiments allow the system to lower its card power consumption depending upon availability of other voltage sources in the system or available components such as inductors to provide internal voltages more efficiently.

RELATED APPLICATION

This application is a Divisional of U.S. application Ser. No. 10/930,524titled “POWER EFFICIENT MEMORY AND CARDS,” filed Aug. 31, 2004 now U.S.Pat. No. 7,196,958 which is commonly assigned and incorporated herein byreference.

FIELD

The present invention relates generally to memories and in particularthe present invention relates to low power consumption memories.

BACKGROUND

The memory devices used on cards such as flash cards in cameras and fortransportable storage require voltages that are much higher than thesupply voltages (Vcc) available. One such type of memory device today isNAND type flash memory. These types of memory devices require voltagesas high as 20 Volts. The Vcc range of operation for these devices isalso dropping with every new generation of device. This is in partbecause end systems are lowering power requirements and this is one waythey achieve that goal. In order to supply sufficient voltages foroperation of the devices, internal pumps are used to pump the supplyvoltages up to a suitable operating voltage. However, the internal pumpsused for NAND memory devices are increasingly inefficient. For example,at a supply voltage of 1.6 Volts (which is typical in current devices),to generate even 5 to 6 volts, the efficiency of the charge pumps areabout 15 percent (%). For the pump to generate 1 mA, it must draw on theorder of 7 mA from the supply voltage source.

NAND devices are meant to be stand alone memory devices that need tooperate from a single power supply, so manufacturers and assemblers haveaccepted low efficiency to maintain the standards to which industryexpects. Typical pumps used on memory devices are Dixon pumps. Thesetypes of pumps have been around for years, and use capacitors and diodesto pump a supply voltage to higher voltages than the internal powersupply available. There are other types of pumps that use inductors thatare much more efficient. Those types of pumps have efficiencies thatapproach 80%. Therefore, one can see that such use could make powerefficiency of the cards on which the devices are used much greater.However, this requires an external inductor which is not a part of theNAND stand-alone memory.

Since the NAND device needs to be stand alone to comply with industrystandards and to allow it to be used across multiple platforms and bymultiple manufacturers, the maintenance of standard efficiency pumps andcommon pin configurations for devices is desirable. However, on thecards used, there may be other voltages available for the card, othersystems of the card, or the memory subsystem.

For the reasons stated above, and for other reasons stated below whichwill become apparent to those skilled in the art upon reading andunderstanding the present specification, there is a need in the art forflash memories and flash memory cards having lower power consumption.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram of a memory card on which embodiments of thepresent invention may be practiced;

FIG. 2 is a block diagram of a memory card having a power efficientcircuit of one embodiment of the present invention;

FIG. 3 is a block diagram of a memory card according to anotherembodiment of the present invention; and

FIG. 4 is a block diagram of a memory on which embodiments of thepresent invention may be practiced.

DETAILED DESCRIPTION

In the following detailed description of the invention, reference ismade to the accompanying drawings that form a part hereof, and in whichis shown, by way of illustration, specific embodiments in which theinvention may be practiced. In the drawings, like numerals describesubstantially similar components throughout the several views. Theseembodiments are described in sufficient detail to enable those skilledin the art to practice the invention. Other embodiments may be utilizedand structural, logical, and electrical changes may be made withoutdeparting from the scope of the present invention.

The following detailed description is, therefore, not to be taken in alimiting sense, and the scope of the present invention is defined onlyby the appended claims, along with the full scope of equivalents towhich such claims are entitled.

As is described in further detail below, a dual mode capable memorydevice or memory card is provided in various embodiments. The memorylooks like, and can be operated like and connected like a standardstand-alone memory. However, if the memory is connected so that certainpins that are normally “no connect” pins are connected to a specificsignal, voltage, or combination thereof, the memory operates in a secondmore efficient mode. Generally, the memory device or memory cardoperates off of a standard internal supply voltage except when adetection mechanism, detection signal, command signal or the like isprovided or detected by the memory device or memory card. Upon a receiptof such a signal or upon a determination to use an external voltage ordifferent internal voltage, or an external voltage in combination withan external inductor, the memory device and memory card embodiments ofthe present invention operate from the other voltage source, inductor,or combination thereof, alone or in conjunction with the standardinternal supply voltage source.

In the embodiments of the present invention and the appended claims, astand-alone memory device is defined as a memory that is configured witha pin out configuration substantially similar to an industry standardpin out configuration, and operates in a traditional operating mannerwhen connected to an industry standard system. Such devices have certainpins that are present in the industry standard system but are notconnected to any internal components of the memory. These are typicallyreferred to as “no connect” pins. Such stand-alone memories include byway of example only and not by way of limitation, DRAM and SDRAMmemories, flash memories, NAND type flash memories, and the like, thathave a standard or substantially standard configuration of pins thatconnect the device to a system or the like.

One embodiment of a memory card 100 is shown in FIG. 1. Memory card 100has a plurality of pins that are used for connection of the card 100 toa device such as a digital camera, a printer, a cellular telephone, orthe like. Memory card 100 has a standard pin out configuration so thatit is capable of use with systems that do not have extra powerefficiencies. Two pins of the standard pin out configuration, herelabeled 102 and 104, are traditionally “no connect” pins in a standardmemory card. In the memory card 100, however, these pins 102 and 104 areconnected internally in this embodiment to a detection circuit thatdetects whether a non-standard voltage is to be used with the card toincrease efficiency of the internal voltage pump 106 of the card 100.

For example, if the memory card 100 is used in a cellular telephonememory that runs on 1.6 volts, but also contains a liquid crystaldisplay (LCD) or the like that operates on a higher voltage, such as 3.0volts, this higher voltage is in various embodiment supplied to theinternal pump, which makes the memory or the memory card more efficient.Alternatively, a higher voltage is supplied through one of the two pins102 or 104, while a signal indicating whether or not to use the externalvoltage is supplied on the other of the two pins 102 or 104.

In another embodiment shown in FIG. 2, a memory card 200 is shown.Memory card 200 is configured with a pin out configuration that workswith standard memory cards as well. An additional pin, 202, which is a“no connect” pin in a standard configuration, is used by this embodimentfor power efficiency changes to the pump configuration of the memorycard 200. In this embodiment, a hardware detection mechanism 206 is usedto detect whether the memory card 200 is connected to some externalpower supply, external inductor, or combination thereof, that can beused for improved pump efficiency, or whether the standard internal pumpconfiguration should be used.

Hardware detection system 206 comprises in one embodiment a pair oftransistors 208 and 210 and a pull down resistor 212. The pull downresistor 212 is optional. The hardware detection system 206 is connectedto pin 202, which is in turn either connected to an external voltage ornot. The pin 202 is connected through resistor 212 to node 214. Node 214is connected to the gate of n-type transistor 208 and to the gate ofp-type transistor 210. If no external voltage device is connected to pin202, or the pin is floating, then the voltage at node 214, through theresistor 212, will be substantially zero, indicating that no externaldevice is connected to the pin 202. In this situation, the memory card200 is configured to operate on its internal power supply Vcc, sincetransistor 210 is on and transistor 208 is off, providing supply voltageVcc to pump 216. If pin 202 is connected to an external voltage, thenthe voltage at node 214 is sufficiently high to turn transistor 210 offand turn transistor 208 on, feeding the voltage at pin 202 to the pump216.

It should be understood that the hardware detection mechanisms describedherein can easily be varied to control which voltage is supplied to theinternal pump. It should also be understood that in certain memories ormemory cards, more than two possible voltages are selectivelyconnectable to the internal pump, and that in other embodiments, aplurality of potential voltages are detected and the highest or mostsuitable voltage for operation of the pump is supplied to the pump.Selection of the voltage to be supplied to the pump is made in variousembodiments through hardware, firmware, software, or through the use ofa command signal provided by the memory controller. The hardwaredetection mechanism of this embodiment can also detect the presence onanother pin of an external inductor, and can reconfigure the operationof the device to use the external inductor alone or in combination withthe external voltage, to provide higher efficiencies. In one embodiment,when both an external voltage and an external inductor are detected, theexternal voltage is used to boost the efficiency of the internal voltagepump, and the external inductor is used with the pumped voltage to evenfurther increase efficiency.

In another embodiment 300 shown in FIG. 3, external pin 302 is used as adetection mechanism only, and the pin 304 is tied to either an externalvoltage or to an inductor. In this embodiment, the card 300 ties thedetection pin 302 to a low signal if the internal pump 306 is to beused. There are two external options possible in this embodiment thatare tied to pin 304. If one of the two external options is to be used,the card 300 ties pin 302 to a high signal. The memory then know fromthe high signal at the detection pin 302 that some external form ofassistance is to be used. Then, a voltage detection mechanism can beused to determine which type of assistance device is tied to the pin304.

If the voltage detection mechanism detects a high, it concludes that apower supply is connected to the pin, and uses that pin as the newsupply for the pump making the pump more efficient and improving powerperformance of the card. If there is simply an inductor hanging off thepin, there is no voltage to detect and the memory concludes that thereis an inductor on the pin. The memory device of the present embodimentthen re-configures its pump to use the inductor instead of the internalpump, again giving the system much better power efficiency, or to runthe internal pump from the inductor in another embodiment. In anotherembodiment, the external inductor is used along with an internal voltagehigher than the supply voltage.

In yet another embodiment, two traditionally “no connect” pins areconnectable to an external voltage and an external inductor. The memorystill has a standard pin out configuration and is operable as a standalone traditional memory when it is connected in a traditional system.Upon detection of the presence of one or the other on the external pins,the device operates using the one external element connected as has beendescribed above with respect to each component individually. However,when both an external inductor and an external voltage are connected tothe pins, both are used. In one embodiment, the external voltage isprovided to the internal pump to provide a higher efficiency pumpedvoltage, and then that voltage is used with the external inductor toprovide an even more efficient operation.

The embodiments of the present invention use a memory having standardpin out connections, but which has extra features that are enabledallowing the memory to be run more efficiently while not losing itsstandard references when an external voltage or other voltage supplyingcomponent is connected to the system.

In the various configurations of memory cards described above, when thecard includes a standard pin configuration with two extra, traditionally“no connect” pins, a resistive pulldown can be used as described. Ifthere is a pullup pin on the system, that pin connected to the resistivepulldown is internally low, and the memory card operates in a normalmode of operation like any other NAND memory card. Because the cardsoperate with a normal pin out configuration, they are usable in standardsystems not configured to use a higher voltage supply for the internalpump. The two extra pins are “no connects” on the system. However, insystems that are configured to use an external or different internalpower supply, the cards can be so used.

Alternatively, a single external power assistance mechanism or voltageis tied to the pin 304, and once the detection pin 302 is tied to a highsignal, the single assistance mechanism tied to pin 304 is used toprovide a starting voltage for the pump 306.

The embodiments of the present invention are all capable of beingconnected to and of running in standard systems, since the onlycomponents that affect behavior are on “no connect” pins in a standardconfiguration for memories and memory cards. It is only when a commandor indication is sent to the memory or memory card, or when an externalvoltage is connected to or detected by the pins of the variousembodiments that operation is commenced in the new modes.

In all of the embodiments of the present invention, a combination ofexternal assistance and the internal supply voltage Vcc may be usedwithout departing from the scope of the invention. In yet anotherembodiment, a voltage higher than the supply voltage Vcc may be presentto operate other components of the system in which a memory card such ascards 100, 200 or 300 are to be used. Such other voltages include, butare not limited to, a display screen voltage supply, an internal batterysupplying power, or the like. In such a configuration, it is a simplematter to modify the circuits and embodiments of the present inventionto provide the other internal voltage to the internal pump, or to use anexternally connected inductor in combination with the other internalvoltage. Such modifications will be understood by those skilled in theart, and are within the scope of the present invention and embodiments.

The memory devices of the various embodiments of the present inventionare configurable through a command from the controller during initialsetup. This command in another embodiment is supplied right before aprogramming or an erase operation. The command in one embodiment tellsthe memory device to use either a supply from outside the card or to usean externally connected inductor instead of the internal pump.

Still further embodiments of the present invention include memorydevices that use the concepts herein. For example, a memory suitable foruse with the embodiments of the present invention is shown in FIG. 4,which is a functional block diagram of a memory device 400, such as aflash memory device, of one embodiment of the present invention, whichis coupled to a processor 410. The memory device 400 and the processor410 may form part of an electronic system 420. The memory device 400 hasbeen simplified to focus on features of the memory that are helpful inunderstanding the present invention. The memory device includes an arrayof memory cells 430. The memory array 430 is arranged in banks of rowsand columns.

An address buffer circuit 440 is provided to latch address signalsprovided on address input connections A0-Ax 442. Address signals arereceived and decoded by row decoder 444 and a column decoder 446 toaccess the memory array 430. It will be appreciated by those skilled inthe art, with the benefit of the present description, that the number ofaddress input connections depends upon the density and architecture ofthe memory array. That is, the number of addresses increases with bothincreased memory cell counts and increased bank and block counts.

The memory device reads data in the array 430 by sensing voltage orcurrent changes in the memory array columns using sense/latch circuitry450. The sense/latch circuitry, in one embodiment, is coupled to readand latch a row of data from the memory array. Data input and outputbuffer circuitry 460 is included for bi-directional data communicationover a plurality of data (DQ) connections 462 with the processor 410,and is connected to write circuitry 455 and read/latch circuitry 450 forperforming read and write operations on the memory 400. Command controlcircuit 470 decodes signals provided on control connections 472 from theprocessor 410. These signals are used to control the operations on thememory array 430, including data read, data write, and erase operations.The flash memory device has been simplified to facilitate a basicunderstanding of the features of the memory. A more detailedunderstanding of internal circuitry and functions of flash memories areknown to those skilled in the art. Detection circuit 490 is used in oneembodiment to detect whether to use an internal voltage pump (not shown)or to use an external voltage supply or inductor as has been describedabove in the various embodiments of the present invention. Theembodiments described above are used in various embodiments in the basicmemory array or system structure described in FIG. 4.

CONCLUSION

The various embodiments of the invention include a memory with aninternal detection mechanism to detect the presence of either anexternal component of an external voltage on some no connect pins,allowing a change in the configuration of the internal voltage pumpsbased on those detections, or which can be used as a standard device aswell. The embodiments allow the system to lower its card powerconsumption depending upon availability of other voltage sources in thesystem or available components such as inductors to provide internalvoltages more efficiently.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat any arrangement, which is calculated to achieve the same purpose,may be substituted for the specific embodiment shown. This applicationis intended to cover any adaptations or variations of the presentinvention. Therefore, it is manifestly intended that this invention belimited only by the claims and the equivalents thereof.

1. A method of operating a dual mode stand-alone memory card,comprising: operating in a normal power mode in which an internal supplyvoltage is connected to an internal pump when no external power supplyis provided to operate the internal pump; and operating in a powerefficient mode when an external component is provided, on a pin that isa no-connect pin in a pin out configuration substantially similar to anindustry standard pin out configuration, to operate the internal pump.2. The method of claim 1, wherein operating in a power efficient modecomprises: determining whether the external component is an inductor oran external voltage supply; operating from the inductor and the internalsupply voltage if the inductor is the external component; and operatingthe internal pump using the external voltage supply if the externalvoltage supply is the external component.
 3. The method of claim 1, andfurther comprising: determining when an external voltage is provided;and switching to the external voltage when it is determined to beprovided.
 4. The method of claim 3, wherein determining when an externalvoltage is provided comprises: receiving a command from a memorycontroller indicating which of the internal voltage and the externalvoltage to use to operate an internal pump of the memory device; andoperating the internal pump from the commanded voltage supply.
 5. Themethod of claim 1, and further comprising: detecting with a detectioncircuit whether to use an external voltage or an internal voltage. 6.The method of claim 5, wherein detecting comprises: monitoring a voltagelevel on a connect pin; and switching from the normal operation modewhen a voltage on the connect pin exceeds an internal supply voltage. 7.The method of claim 5, wherein detecting comprises: monitoring an enablepin; and switching to operation from an external component connected toa supply pin when a signal on the enable pin enables the power efficientmode of operation.
 8. The method of claim 7, wherein switching tooperation from an external component comprises: determining whetherexternal voltage is an inductor or an external supply; operating fromthe inductor and the internal supply voltage if the inductor is theexternal component; and operating the internal pump from the externalsupply if the external supply is the external component.
 9. A method ofoperating a dual mode stand-alone memory card, comprising: operating ina normal power mode in which an internal supply voltage is connected toan internal pump when no external power supply is provided to operatethe internal pump; and switching to operation in a power efficient modewhen an external component is provided on at least one of two pins, eachof the two pins being a no-connect pin in a pin out configurationsubstantially similar to an industry standard pin out configuration, tooperate the internal pump.
 10. The method of claim 9, wherein switchingto operation from an external component comprises: determining whetheran external component is connected to the first pin, the second pin, orboth pins; operating from the connected external pin when an externalcomponent is connected to one of the first or the second pins; andoperating from both of the external components when an externalcomponent is connected to each of the first and the second pins.
 11. Amethod of operating a memory device, comprising: receiving a commandfrom a memory controller indicating which of a plurality of voltagesupplies to use to operate in a power efficient mode of the memorydevice; and operating the internal pump according to the power efficientmode using the voltage supply indicated by the command.
 12. The methodof claim 11, wherein operating in a power efficient mode comprises:determining whether the voltage supply indicated by the command is aninternal high voltage supply or an external component; using theinternal high voltage supply to provide voltage to the internal pumpwhen the voltage supply indicated by the command is the internal highvoltage supply; and using the external component when the externalcomponent is the voltage supply indicated by the command.
 13. The methodof claim 12, wherein using the external component further comprises:determining whether the external component is an inductor or an externalvoltage supply; operating from the inductor and the internal highvoltage supply if the inductor is the external component; and operatingthe internal pump using the external voltage supply if the externalvoltage supply is the external component.
 14. A method of operating adual mode memory card, comprising: operating in a normal power mode inwhich an internal supply voltage is connected to an internal pump whenno external power supply is provided to operate the internal pump; andoperating in a power efficient mode when an external component isprovided to operate the internal pump.
 15. A method of operating astand-alone memory card, comprising: operating in a first operating modeusing an internal power supply voltage; monitoring a memory card pin foran operating mode change signal; and changing operation to a secondoperating mode more efficient than the first operating mode when theoperating mode change signal is received.
 16. The method of claim 15,wherein monitoring comprises: detecting an external component connectedto the memory card pin using a detection mechanism.
 17. The method ofclaim 15, wherein operating in a first operating mode comprises: passingan internal supply voltage to an internal voltage pump of the memorycard.
 18. The method of claim 15, wherein changing operation comprises:passing an external voltage on the memory card pin to an internalvoltage pump of the memory card when an external voltage is detected onthe memory card pin.
 19. The method of claim 18, wherein changingoperation further comprises: comparing the external voltage to a voltageof the internal voltage pump, and changing only when the externalvoltage exceeds the voltage of the internal voltage pump.
 20. The methodof claim 15, wherein changing operation comprises: passing an externalvoltage to the memory card on a memory card supply pin that is ano-connect pin in an industry standard pin out configuration memory cardpin when an external detection signal is detected on a to an internalvoltage pump of the memory card when an external voltage is detected ona memory card connect pin that is a no connect pin in an industrystandard pin out configuration.
 21. The method of claim 16, and furthercomprising: detecting a presence of an external conductor on a secondconnect pin; and reconfiguring operation of the device in the secondoperating mode to use either the external inductor alone or incombination with the external voltage.